1. Field of the Invention
The present invention is related to a driving method, driving device and touch sensitive display device using the same, and more particularly, to a driving method, driving device and touch sensitive display device using the same capable of preventing effects of noise interference on a touch sensing function.
2. Description of the Prior Art
With advances in manufacturing technology, a touch panel and a display panel are successfully integrated in an electronic device to enable the user to directly indicate desired tasks by touching the electronic device. In general, pixel units of the display panel and touch sensors of the touch panel are both arranged in two-dimensional matrixes, and sequences for updating frame data and detecting a touch point are determined based on scanning signals. Therefore, in R.O.C (Taiwan) patent application no. 099,110,384, the applicant of the present invention discloses a device and method for sharing the scanning signals such that the touch sensors can be directly triggered by scanning signals of the display panel instead of touch scanning signals generated by an extra driving circuit.
Please refer to FIG. 1, which is a schematic diagram of a touch sensitive display device 10 according to R.O.C patent no. 099,110,384. The touch sensitive display device 10 includes a display panel 100, a touch panel 110, a source driver 120, a gate driver 130 and a touch processor 140. The display panel 100 includes pixel units 102 arranged in a two-dimensional matrix. Similarly, the touch panel 110 includes touch sensors 112 arranged in a two-dimensional matrix. The source driver 120 generates source driving signals VS_1-VS_M according to an image signal FRM to indicate color intensities of the pixel units 102. The gate driver 130 generates scanning impulse VG_1-VG_N according to a synchronization signal SEQ to indicate an updating sequence of the pixel units 102. Meanwhile, the odd scanning signals VG_1, VG_3 . . . are further utilized for triggering the touch sensors 112. The triggered touch sensors 112 generate response impulses VR_1-VR_K. Since contacts on the touch sensors 112 result in capacitance or resistance variations thereof, response impulses generated by the touched touch sensors 112 are distinctive from response impulses generated by the untouched touch sensors 112. As a result, the touch processor 140 can determine the touch point located on the touch sensors 112 based on variations of the response impulses VR_1-VR_K and the odd scanning impulses.
Note that, the touch panel 110 is stacked upon the display panel 100 in the touch sensitive display device 10. Since the touch panel 110 requires lower resolution than the display panel 100, a plane density of the touch sensors 112 is lower than a plane density of the pixel units 102 to save manufacturing costs. That is, only a part of the scanning impulses VG_1-VG_N are further utilized for triggering the touch sensors 112.
Other than the stacked structure, the touch sensitive display device can be designed as an embedded structure. According to the embedded structure, the touch sensors are embedded within the pixel units. However, regardless of whether the stacked structure or the embedded structure is applied, the touch sensors are triggered while the pixel units are updated according to R.O.C. patent application no. 099,110,384. Therefore, voltage variations of the scanning impulses easily couple into the touch sensors, resulting in erroneous determination of the touch point. In other words, the scanning impulses VG_1-VG_N are used for dual purposes, and thus interfere with the touch sensors 112.
Therefore, reducing interference of the scanning impulses on the touch sensors has been a major focus of the industry.